Left Atrial Appendage Thrombus and Dense Spontaneous Echo Contrast in Anticoagulated Atrial Fibrillation Patients...

Background/Objectives: Predictors of left atrial appendage thrombus (LAAT) in adequately anticoagulated patients with atrial fibrillation (AF) referred for direct current cardioversion (DCCV) remain insufficiently defined, particularly in populations with a high prevalence of cardiac implantable electronic devices (CIEDs). The aim of this study was to identify clinical and echocardiographic determinants of LAAT and/or dense spontaneous echocardiographic contrast (SEC) in patients with persistent AF referred for DCCV. Methods: This prospective observational study included 510 consecutive patients with persistent AF who had received at least 3 weeks of effective anticoagulation and underwent transthoracic and transesophageal echocardiography prior to elective DCCV. The primary endpoint was the presence of LAAT and/or dense SEC (Fatkin grade 3-4). Independent predictors were identified using multivariable logistic regression. Results: LAAT and/or dense SEC were detected in 192 patients (37.6%)-of whom 73 had overt LAAT, 19 had borderline LAAT, and the remainder had dense SEC (Fatkin grade 3-4). Independent predictors included lower left ventricular ejection fraction (OR 0.95 per 1% increase, 95% CI 0.94-0.97, p < 0.0001), reduced right ventricular fractional area change (OR 0.93 per 1% increase, 95% CI 0.91-0.94, p < 0.0001), larger left atrial area (OR 1.05 per 1 cm² increase, 95% CI 1.01-1.09, p = 0.011), and female sex (OR 1.78, 95% CI 1.14-2.79, p = 0.012). Moderate or greater mitral regurgitation was associated with a lower risk (OR 0.50, 95% CI 0.30-0.82, p = 0.007). The CHA₂DS₂-VASc score and the presence of right ventricular leads were not independently associated with LAAT/SEC. The model showed good discrimination (AUC 0.81, 95% CI 0.77-0.84). Conclusions: In anticoagulated patients with persistent AF, LAAT and/or dense SEC remain common and are primarily driven by echocardiographic markers of biventricular dysfunction and left atrial remodeling rather than by traditional clinical risk scores or the presence of cardiac devices.